Method of manufacturing strip from metal powder

ABSTRACT

A method is provided for forming metal strip from metal powders by spraying the powder as molten metal onto a cooled moving metal foil and thereafter consolidating the foil and sprayed metal by applying pressure.

United States Patent [191 Wentze11 [451 July 3,1973

[ METHOD OF MANUFACTURING STRIP FROM METAL POWDER [75] Inventor: JosephM. Wentzell, Remsen, NY.

[73] Assignee: Homogeneous Metals, lnc.,

Herkimer, NY.

[22] Filed: Dec. 28, 1970 [21] Appl. No; 101,954

1 52 vs. Cl. 29/423,,29/149.5 s, 29/5272,

[51] Int. Cl 823p 17/00 [58] Field of Search 29/527.2, 527.7, 29/D1G.39, 149.5 S, 423; 164/46; 117/105, 105.3

[56] References Cited UNITED STATES PATENTS 3,221,392 l2/1965 Gould29/14955 Primary Examiner-Char1es W. Lanham Assistant ExaminerD. C.Reiley, lll Att0rneyBue1l, Blenko & Ziesenheim [5 7] ABSTRACT A methodis provided for forming metal strip from metal powders by spraying thepowder as molten metal onto a cooled moving metal foil and thereafterconsolidating the foil and sprayed metal by applying pressure.

8 Claims, 2 Drawing Figures METHOD OF MANUFACTURING STRIP FROM METALPOWDER This invention relates to methods of manufacturing strip frommetal powder and particularly to a method Norm ally the metals known assuperalloys, i.e., alloys of iron, nickel or cobaltwhich will maintainusable me chanical properties at elevated temperatures, are cast intoingots which are then either forged or bloomed into slabs, cut andconditioned, rolled into either bands or plates, conditioned and thenfinally rolled into strip and cut. There are several heat treatmentsnecessary throughout the process and a final heat treatment dependent onthe customers requirements. All of this costs time and money. Perhapsmore important is the fact that this large amount of hot working tendsto deplete boron from superalloys through oxidation. Boron is essentialto stress rupture life at elevated temperature.

Sheet and strip of nickel, aluminum and iron have been rolled directlyfrom metal powder by feeding the powder through a mill with its rolls ina horizontal plane. When rolling strip in this fashion it is necessarythat the green strength of the strip be sufficient to allow subsequentprocessing. This means that the powder must have a special configurationconducive to providing high green strength. Superalloy powder havinghigh purity is generally made by a dry process which results inspherical powder having poor cold compactability lacking the specialconfiguration necessary to provide green strength.

I have invented a method of making metal strip from metal powder whichmakes it possible to form strip from powder without regard to its shape.In my method I feed the metal powder through a plasma gun or similarmetallizing gun onto a substrate of aluminum, copper or iron strip orfoil, the foil being in intimate contact with a cooling element at thetime the hot metal particles are sprayed onto the substrate. The metalspraying operation is carried out in an inert atmosphere such as in aninert gas purged chamber. Preferably the sprayed foil is cold rolled toapredetermined reduction and then resprayed if greater thickness isdesired. The amount of spray, applied and the amount of cold rolling aredependent upon the particular alloy and the desired thickness. Eachsubsequent spraying or metallizing after rolling will stress relieve thestrip. Since all heat treatment is carried out in an inert atmosphereoxidation is eliminated. The substrate may be removed from the finishedstrip by preferential etching using for example hydroxide for aluminumfoil and nitric acid for copper or iron.

In the foregoing general description of my invention I have set outcertainobjects, purposes and advantages of my invention. Other objects,purposes and advantages will be apparent from a consideration of thefol-. lowing description and the accompanying drawings in which:

FIG. 1 is a schematic section through an apparatus for carrying out thepractice-of this invention, and

FIG. 2 is a section through a strip made from metal powder according tomy invention.

Referring to the drawings I have illustrated a sheet of foil 10 beingdelivered from coil 11 through a chevron seal 12 into the interior ofchamber 13 where it passes over a water cooled roll 14. The foil 10 issprayed with molten superalloy 15 from a plasma gun l6 supplied withpowdered superalloy from a hopper 17. The molten superalloy l5solidifies on the foil 10 to form a layer of superalloy which is passedbetween pressure rolls 18 to cold roll the newly formed superalloy strip15.

If a greater thickness of strip 15 is desired than can be applied withone pass in front of plasma gun 16, then the coating operation is simplyrepeated as many times as is necessary. The spraying of moltensuperalloy onto the strip 15 will stress relieve the previously formedlayer 15 without danger of oxidation.

If the substrate 10 is to be removed the composite strip is passedthrough an appropriate etch solution to dissolve it away from thesuperalloy strip 15 after cold rolling.

In the foregoing specification I have set out certain preferredpractices and embodiments of my invention, however, it will beunderstood that this invention may be otherwise embodied.

I claim:

l. A method of forming strip from metal powders comprising the steps ofa. converting a metal powder to a molten metal spray,

b. applying the-molten metal spray in an inert atmosphere to a movingmetal foil in a substantially uni form layer to form a major componentof the combined thickness,

c. cooling the metal foil and molten spray applied thereto to solidifysaid molten spray while in said inert atmosphere, and

d. consolidating said foil and sprayed metal by' applying pressurethereto.

2. A method as claimed in claim 1 wherein the foil is cooledsimultaneously with the application of the molten spray thereto.

3. A method as claimed in claim 1 wherein the foil is coated with metalspray while changing direction of the foil.

4. A method as claimed in claim 1 wherein the metal foil is a memberselected from the group aluminum, nickel, copper and iron.

5. A method as claimed in claim 1 wherein the metal is consolidated bypressure rolling.

6. A method claimed in claim 1 wherein the metal powder is passedthrough a plasma gun to form a molten spray of metal.

7. A method as claimed'in claim '1 wherein the foil is removed byetching after consolidation of the metal.

8. A method as claimed in claim 1 wherein the foil is passed over awater cooled roll in an inert atmosphere and the molten metal sprayedonto the foil while the cooled roll.

foil is on the water

2. A method as claimed in claim 1 wherein the foil is cooledsimultaneously with the application of the molten spray thereto.
 3. Amethod as claimed in claim 1 wherein the foil is coated with metal spraywhile changing direction of the foil.
 4. A method as claimed in claim 1wherein the metal foil is a member selected from the group aluminum,nickel, copper and iron.
 5. A method as claimed in claim 1 wherein themetal is consolidated by pressure rolling.
 6. A method claimed in claim1 wherein the metal powder is passed through a plasma gun to form amolten spray of metal.
 7. A method as claimed in claim 1 wherein thefoil is removed by etching after consolidation of the metal.
 8. A methodas claimed in claim 1 wherein the foil is passed over a water cooledroll in an inert atmosphere and the molten metal sprayed onto the foilwhile the foil is on the water cooled roll.